<!doctype html>
<html>
<head>
  <meta charset="utf-8"/>
  <title>清 Cookie</title>
  <style>
    body { width:120px; padding:10px; text-align:center; }
    button { width:100%; padding:8px 0; }
  </style>
</head>
<body>
  <button id="clearBtn">清除 Cookie</button>
  <script src="popup.js"></script>
</body>